The study will enroll both males and females and include all ethnic and racial groups through clinical practices in the centers. The study will enroll subjects in the older adult age range commonly affected by glaucoma - 40 years or older. The study will exclude people with life-threatening or debilitating illness that would make 5-year participation unlikely or cooperation with tests difficult. For similar reasons those older than 79 years are excluded. The study also excludes those with any disease that might confound the diagnosis of glaucoma. Otherwise people with any health status are eligible for enrollment. Three groups of participants are recruited in the AIG study: normal (N), glaucoma suspects & preperimetric glaucoma (GSPPG) and perimetric glaucoma (PG).